Abu Huraira reported God's Messenger as saying, “If anyone prays six rak'as after the sunset prayer, not saying anything evil during them, they will be treated for him as equivalent to twelve years’ worship.”
Tirmidhi transmitted it, saying, “This is a gharib tradition which I know only from the traditions of ‘Umar b. Abu Khath'am; and I heard Muhammad b. Isma'il (i.e. Bukhari) say that his traditions are rejected. He declared him to be very weak.”